SPLEEN BY GOWRI R ASST LECTUER BGI SPLEEN

SPLEEN BY : GOWRI. R ASST. LECTUER BGI

SPLEEN • Spleen is the largest single mass of lymphoid tissue in the body. It is red- brown in color , soft and friable. Normally , it is a bloodforming organ in fetal life and blood- destroying organ in postnatal life. Since it is in the blood stream , it filters the blood from blood – borne antigens and microorganism.

• Location The spleen is a situated in the left hypochondrium opposite to the level of 9 th , 10 th and 11 th ribs. Its long axis is parallel to the 10 th rib. Dimensions Spleen is a wedge- shaped organ. It is about 1 inch thick , 3 inches broad , 5 inches long , 7 ounces in weight and is related to 9 th to 11 th ribs. External features The spleen has two ends , three borders and two surfaces. • Anterior or lateral end : it is expanded • Posterior or medial ends : it is rounded and is directed backward and medially.

• Inferior borders : it is rounded • Superior border : it is notched and indicates lobulated origin of spleen. • Intermediate borders : It is rounded and directed to the right. the outer diaphragmatic surface is convex and smooth. • Visceral surface : it is irregular and is related to important organs , which forms an impression on visceral surface. üGastric impression ; it is created by the fundus of stomach ; it is the largest visceral impression üRenal impression : it is due to left kidney üColic impression : the splenic flexure of colon is related to spleen near the anterior end. üPancreatic impression : it lies between hilum and the colic impression , due to tail of the pancreas.

• Hilum : it is a cleft present along the long axis of spleen , which transmits splenic vessels and nerves , and also provides attachment to gastro splenic and lienorenal ligaments. • Hilum of spleen The structure entering and leaving the spleen at hilum are : • Splenic artery , a branch of celiac artery • Splenic vein • efferent lymph vessels.

Blood supply Arterial supply is by the splenic artery , the largest branch of celiac trunk. It is tortuous and passes the largest through lienorenal ligament ( a peritoneal ligament extending between left kidney and spleen )to the hilum , where the artery divides into four to five branches. Venous drainage The splenic vein emerges from the hilum of the spleen. It joins with the superior mesenteric vein behind the neck of the pancreas to form the portal vein.

Functions of spleen • The spleen is a center where both B – and T –lymphocytes multiply , and play an important role in the immune responses. • The spleen contains the largest aggregations of macrophages of the mononuclear phagocyte system. the main functions of these cells is in destruction of RBCs that have completed their useful life. • Macrophages also destroys worm out leukocytes and bacteria. • In fetal life , the spleen is a center for production of all blood cells. v. NOTE ; enlargement of spleen is called splenomegaly